Aw man, reminds me of Ironforge (Dwarven city in World of Warcraft). Good work so far, but with a little tweaking of the materials and some object/building that gradually leads the viewer to the castle… I think you can push this one to greatness.
On a more critical note though; from afar the materials are convincing, but lack credibility up close ( very sharp edges between the snow and the rocks. Also… I think the snow might be able to use a slightly blueish sss here and there, but nothing too obvious.
Anyhow… keep going, will keep watching this one.